{
"metadata": {
"name": "",
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 12 : Refrigeration"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.1 Page No : 216"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Given\n",
"m = 500.0;#mass of ice produced per hour in Kg\n",
"T1 = 15.0;#Initial temperature of water\n",
"T2 = -5.0;#Final temperature of ice\n",
"Ci = 0.5;#Specific heat of ice in Kcal/Kg deg celsius\n",
"Cw = 1.0;#Specific heat of water in Kcal/Kg deg celsius\n",
"L_f = 79.71;#Latent heat of fusion in Kcal/Kg\n",
"Tf = 0.0;#Frezzing point of ice in deg celsius\n",
"\n",
"#To Calculate the theoretical horse power required\n",
"Q2 = m*(Cw*(T1-Tf)+L_f+Ci*(Tf-T2));#Heat to be extracted per hour in Kcal\n",
"#From equation 12.1 (page no 220)\n",
"COP = (T2+273)/((T1+273)-(T2+273));\n",
"W = Q2/COP;#Work in Kcal/hr\n",
"W1 = W*(427/(60*4500.0));\n",
"print \"The therotical horse power required is %f hp\"%(W1);\n",
"#end\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The therotical horse power required is 5.736411 hp\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.2 Page No : 217"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from scipy.integrate import quad\n",
"\n",
"#Given\n",
"Ta = 298.0;#Initial temperature in K\n",
"Tb = 203.0;#Final temperature in k\n",
"T1 = 298.0;#Water temperature in K\n",
"n = 1.0;#Kgmole of CO2\n",
"#Cp = 5.89+0.0112T ; Specific heat of CO2 in Kcal/Kgmole K\n",
"\n",
"#To Calculate the compressor load\n",
"#From equation 12.2a and b (page no 221)\n",
"def f(T):\n",
" y = ((T1-T)/T)*n*(5.89+0.0112*T);\n",
" return y\n",
"W = quad(f,Ta,Tb)[0];\n",
"print \"The compressor load is %f Kcal/Kgmole\"%(W);\n",
"#end\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The compressor load is -164.797031 Kcal/Kgmole\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.3 Page No : 221"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"#Given\n",
"#Consider the figure 12.4 (page no 226) \n",
"m = 5.0;#tonnes of refrigeration\n",
"T1 = 273-10.0;#temperature of the saturated vapour in K\n",
"T2 = 273+35.0;#temperature of the super heated vapour in K\n",
"T3 = 273+25.0;#temperature of the saturated liquid in K\n",
"T4 = 273+25.0;#temperature of the wet vapour in K\n",
"H1 = 341.8;#enthalpy of the saturated vapour in Kcal/Kg\n",
"H2 = 409.0;#enthalpy of the super heated vapour in Kcal/Kg\n",
"H3 = 350.0;#enthalpy of the saturated liquid in Kcal/Kg\n",
"H4 = 71.3;#enthalpy of the wet vapour in Kcal/Kg\n",
"\n",
"#To Calculate the C.O.P, mass of refrigerant required, compressor horse power required and the C.O.P & compressor horse power for a reversed Carnot cycle\n",
"#(i)Calculation of the C.O.P of the compression cycle\n",
"#From equation 12.6 (page no 226)\n",
"COP = (H1-H4)/(H2-H1);\n",
"print \"i)C.O.P of the compression cycle is %f\"%(COP);\n",
"\n",
"#(ii)Calculation of mass of refrigerant required\n",
"#From equation 12.7 (page no 226)\n",
"M = (m*50.4)/(H1-H4);\n",
"print \" ii)The mass of refrigerant required is %f Kg/mt\"%(M);\n",
"\n",
"#(iii)Calculation of the compressor horse power\n",
"#From equation 12.5 (page no 226)\n",
"C_hp = (H2-H1)*M*(427/4500.0);\n",
"print \" iii)The compressor horse power is %f hp\"%(C_hp);\n",
"\n",
"#(iv)Calculation for reversed Carnot cycle\n",
"#From equation 12.1 (page no 220)\n",
"COP = T1/(T3-T1);\n",
"print \" iv)C.O.P for the reversed Carnot cycle is %f\"%(COP);\n",
"Q2 = m*50.4*(427/4500.0);#in hp\n",
"C_hp = Q2/COP\n",
"print \" Compressor horse power for the reversed Carnot cycle is %f hp\"%(C_hp);\n",
"#end\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"i)C.O.P of the compression cycle is 4.025298\n",
" ii)The mass of refrigerant required is 0.931608 Kg/mt\n",
" iii)The compressor horse power is 5.940430 hp\n",
" iv)C.O.P for the reversed Carnot cycle is 7.514286\n",
" Compressor horse power for the reversed Carnot cycle is 3.182205 hp\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.4 Page No : 225"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Given\n",
"#Water at 20 deg cel is chilled to 10 deg cel by flash evaporation\n",
"Pv = 0.012;#Vapour pressure of water at 10 deg celsius in Kgf/sq.cm\n",
"H1 = 20.03;#Enthalpy of liquid water at 20 deg cel in Kcal/Kg\n",
"H2 = 10.4;#Enthalpy of liquid water at 10 deg cel in Kcal/Kg\n",
"Hv = 601.6;#Enthalpy of saturated vapour at 10 deg cel in Kcal/kg\n",
"\n",
"#To calculate the pressure in the math.tank and the amount of make up water required\n",
"P = Pv;#pressure in the math.tank = vapour pressure of water\n",
"print \"The pressure in the math.tank is %f Kgf/sq.cm\"%(P);\n",
"#From equation 12.8 (page no 234)\n",
"x = (H1-H2)/(Hv-H2);\n",
"print \" The amount of make up water required is %f Kg\"%(x);\n",
"#end\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The pressure in the math.tank is 0.012000 Kgf/sq.cm\n",
" The amount of make up water required is 0.016289 Kg\n"
]
}
],
"prompt_number": 5
}
],
"metadata": {}
}
]
}